June 3, 200421 yr After trying to locate the coolant leak in my Brat, I ended up removeing both heads looking for the leak, and found that both heads were warped more than 3 times the allowed limit. So off to be resurfaced they went - had .020 milled off them (max allowed). So according to my calculations, that will raise my compression from 8.7 to 9.12...... When I build my hign output EA81, taking .020 off the heads, and finding pistons that are .015 taller will get me to 9.5.... GD
June 3, 200421 yr What I want to know is why those FINE subaru parts are being displayed on a container that seems to be marked "Debris". What's up with THAT???
June 3, 200421 yr IIRC, watch for the intake fitment when you reassemble, it's going to be tight. Don't know if that's enough to have to make the holes in the intake a bit oval to fit correctly. the tolerances aren't that tight. Hmm. Keep us updated. Good info to know. Jay
June 4, 200421 yr Author I wanted to document before and after cleaning - I degreased them myself, so I wanted a side by side of one clean and one not. They are both clean now - and one is installed. Hydro lifter adjustment on EA81's is interesting..... GD
June 4, 200421 yr Author IIRC, watch for the intake fitment when you reassemble, it's going to be tight.No issues. I just tried it, and the size of the intake holes are large enough to cover .020 - at least that part worked out well. BTW - the FSM says .020 is the maximum you can remove, so it makes sense that the manifold fits - it was designed that way. The question is how did Subaru arrive at that figure? Was that the maximum you could do and still fit the manifold, or was there some other more mechanical reason for picking that number? If ovaling out the manifold holes was all that was needed, .035 would give me close to 9.5 compression without the need for piston replacement. Hhhhmmm.... GD
June 4, 200421 yr it's not the bolt holes on the manifold you need to be concerned with, it's the lineup of the air/fuel and coolant passages.
June 4, 200421 yr Author I see - you're talking about me going to .035.... there is plenty of metal to grind away a 35 thousandths shelf so it would line up again. Easy enough to do. GD
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